Exercise, at least at some level, can reduce chances of sustaining a heart attack by up to 60%, and dying as a result of a heart attack by up to 70%. These statistics are found in the Paffenberg report, American Journal of Epidemiology, vol. 108, pps. 161-175, 1978. The above benefits accrue in approximately linear fashion up to a maximum weekly calorie burn of 2500. Using data for stationary cycling from a book entitled AEROBICS WAY by Dr. Kenneth H. Cooper, Bantam Books, New York, 1981, a rough calculation shows that a competitive cyclist, one who can spin his legs at 105 rpm for an hour, would burn 2500 calories with five one-hour sessions of stationary cycling at that speed. The average person using a stationary exercise bicycle would have to exercise considerably longer than five hours per week or he would have to be satisfied with significantly reduced benefit.
When the objective of exercise is minimizing occurrences and fatalities associated with heart attack, exercise takes on added proportions. The most common exercise device, the exercise bicycle, requires an extensive amount of time from the user in order to deliver significant benefit. Thus, a strong need exists for an exercise bicycle that can offer an additional mode of use which gives more exercise benefit per unit of time.
It is worth noting that in quantifying exercise intensity levels for stationary cycling, in the above-mentioned book Dr. Cooper states that stationary cycling is awarded approximately half the points as regular cycling. This difference in exercise intensity offered by rolling bicycles compared to stationary bikes is a result of the advantage that the rolling bicycle derives from its rolling momentum which assists the user in moving his feet through top/bottom dead center. Helping the stationary bike to equal the rolling bike in exercise intensity by giving the stationary bike an action through pedal top/bottom dead center similar to that of the rolling bicycle is a significant benefit since higher sit-down exercise intensities can be obtained.
Moreover, the results of the research of physiologists Astrand and Saltin indicate why body lifting, e.g. stand-up hill pedalling, offers significantly more exercise benefit than sit-down pedalling. Astrand and Saltin discovered that the length of time an exerciser can continue at high intensity is proportional to the mass of muscle used. Stand-up, body lift pedalling uses a larger muscle mass than sit-down leg spinning. Therefore, stand-up, body lift pedalling gives opportunity for longer exercise than sit-down pedalling. Thus, any device that facilitates stand-up, body lift pedalling and offers the user help over the top/bottom dead center positions, increases the time the user can exercise at high intensity and consequently increases the intensity an exerciser can maintain for any given period of time. Thus, if in addition to making a stationary bicycle behave like a rolling bike in relation to force required to move the pedals through top/bottom dead center, a simulation of the "stand-up", hill climbing mode of bicycling were added to the conventional exercise bicycle, a longer duration of exercise at high intensity would be possible.
Present technology exists that teaches the attainment of a stand-up, body lift mode of exercise through various climbing simulators such as illustrated in U.S. Pat. Nos. 1,409,992; 1,820,372; 1,854,473; 3,227,447; 3,381,958; 3,395,698; 3,497,215; 3,511,500; 3,529,474; 3,704,886; 3,758,112; and 3,865,366. Note that the device described in U.S. Pat. No. 3,360,263 involves an eccentric brake drum which helps reduce top/bottom dead center problems associated with normal, sit-down exercise bicycles. Other U.S. patents dealing with exercise bicycles and control systems include U.S. Pat. Nos. 359,800; 3,419,732; 3,501,142; 3,518,985; 3,744,480; 3,767,195; 3,802,698; 3,845,756; 3,848,467; 4,112,928; and 4,244,021. However, nowhere in these references is taught how exercise bicycle design can be modified to offer two modes of exercise, with one including the desirable body lift exercise where comfortable high intensity levels can be maintained for long periods of time through a stand-up pedalling action during which the user expends energy by cyclically raising his body. It should be noted that the technique for stand-up pedalling for hill climbing is called "honking" and is a natural body response to pedalling a one speed bike up an incline.
Exercise bicycles that offer high intensity, body lift exercise as an additional mode of use are desirable because stationary bicycles are the type of machine most often associated with exercise in the minds of potential users. It should also be noted that the present low intensity, sit-down, leg churn exercise bicycles are relatively ineffective because of the low intensity and the short duration exercise afforded when the user stops due to leg fatigue.